Cast Demonic Consultation by paying {B}, naming a card not in your library and exiling your library.
Activate Jarad by paying {1}{B}{G} and sacrificing Cosmogoyf, causing each opponent to lose life equal to Cosmogoyf's power.

Near-infinite lifeloss

Exile your library

Jarad, Golgari Lich Lord

Cosmogoyf

Demonic Consultation

Activate Phyrexian Devourer by exiling the top card of your library.
Repeat step 1 until your library is empty or the number of cards you own in exile is equal to or greater than each opponent's life total.
Activate Jarad by paying {1}{B}{G} and sacrificing Cosmogoyf, causing each opponent to lose life equal to Cosmogoyf's power.
Activate Phyrexian Devourer's second ability by exiling the top card of your library, causing you to put a number of +1/+1 counters on Phyrexian Devourer equal to that card's mana value.
Repeat step 1 until Phyrexian Devourer's power is greater than each opponent's life total.
Phyrexian Devourer's first ability triggers.
Holding priority, activate Jarad by paying {1}{B}{G} and sacrificing Phyrexian Devourer, causing each opponent to lose life equal to Phyrexian Devourer's power.

Near-infinite damage

Phyrexian Devourer

Cast Leveler by paying {5}.
When Leveler enters, it triggers, exiling your library.
Activate Jarad by paying {1}{B}{G} and sacrificing Cosmogoyf, causing each opponent to lose life equal to Cosmogoyf's power.

Leveler

Activate Arc-Slogger by paying {R} and exiling the top 10 cards of your library, dealing 2 damage to any target.
Repeat step 1 as desired. It is recommended to do this until your library is empty or until the amount of cards you own in exile is greater than or equal to each opponent's life total, whichever comes first.
Activate Jarad by paying {1}{B}{G} and sacrificing Cosmogoyf, causing each opponent to lose life equal to Cosmogoyf's power.

Combos with "Cosmogoyf"